CSCI 391: Practical Cryptology: Quiz 2 Preparation

You can use Wolfram|Alpha: Computational Knowledge Engine and you can use Vigerene Cipher Web Resources to check your answers.

1. Encrypt the message MEETINGS using Vigenere Cipher and the keyword POOR. What are the cipherletters corresponding to both letters E? Did you get the same letter? Explan your answer. Show calculations for the first 5 letters. Use general formula (not the Vigenere table).

2. Decrypt the message TIGBQU that was encrypted using Vigener Cipher and the keyword CITY. Explain in details. Show calculations for the first 5 letters. Use general formula (not the Vigenere table).

3. Suppose you are using Vigener Cipher and your plaintext is ADVANCES. Give an example of the keyword to encrypt all letters A by the different letters. Explain.

4. Suppose you are using Vigener Cipher and the plaintext is ADVANCES. Give an example of the keyword to encrypt all letters A by the same cipherletter.

5. Suppose you are using Vigener Cipher and the plaintext is UTILITIES. Give an example of the keyword to encrypt all letters T by the same cipherletter M.